1. Field of the Invention
The device of this invention resides in the area of valve adjustment means for internal combustion engines having overhead cams or rocker arms and more particularly relates to a valve spring retainer including means for adjustment of the gap between the cam shaft and/or rocker arm and valve stem, and an hydraulic embodiment of same.
2. History of the Prior Art
In typical overhead cam engines the valves are operated by a rocker arm pushing on the valve stem or cam shaft pushing on bucket tappets. The rocker arm is usually actuated by a cam located in association therewith. In order to provide for the thermal expansion of the valve stem due to the heat created by the fuel combustion within the engine, gaps are usually provided between the valve stem and rocker arm. Most adjustments of the gap mentioned above are accomplished by means of locked screw or the use of shims placed within the bucket member positioned over the valve spring retainer. Although such adjustments are relatively simple, in many instances one must remove the cam shaft from the vehicle in order to place the shims in position under the bucket. In other systems the bucket may be adjusted by providing a screw member threaded across the top of the valve stem at an angle so that if it is rotated upward it raises the bucket or if it is rotated downward, it lowers the bucket. A gap adjustment device that is pertinent to the device of this invention is disclosed in U.S. Pat. No. 2,722,204, issued to Adolph Wente entitled "Means for Adjusting the Lost Motion of the Valve Actuation in Internal Combustion Engines." This system provides adjusting means that utilize a threaded valve stem on which a nut-like member is rotatably threaded. Systems such as this must provide means to prevent rotation of the valve stem when the nut is rotated thereon for adjustment.